Air-blade, silencer and separator apparatus and method

ABSTRACT

Silencing and separation in a cold-air, essential-oil, diffuser apparatus and method pass flow through a channel having comparatively high aspect ratios of length to thickness and width to thickness. Curved, tapered, non-parallel, and quasi random surfaces reduce probability and power of resonant frequencies. Offsetting flow through a channel is followed by impingement against an obstructing surface, redirection elsewhere within a drift (separation) chamber, and exiting through a smaller, and differently oriented exit port. Silencing is improved by changes of cross-sectional area creating high-pass and low pass acoustic filters, changes of direction, and absorption of acoustic energy in fluid-droplet-laden air.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/459,013, filed Feb. 14, 2017, and is acontinuation-in-part Application of U.S. patent application Ser. No.29/554,486, filed Feb. 11, 2016, both of which are hereby incorporatedherein by reference. This application incorporates by reference: U.S.patent application Ser. No. 12/247,755, filed Oct. 8, 2008, issued Feb.1, 2011, as U.S. Pat. No. 7,878,418; U.S. patent application Ser. No.13/854,545, filed Apr. 1, 2013; U.S. patent application Ser. No.14/260,520, filed Apr. 24, 2014; U.S. Provisional Patent ApplicationSer. No. 62/265,820, filed Dec. 10, 2015; U.S. patent application Ser.No. 14/850,789, filed Sep. 10, 2015; and U.S. Provisional PatentApplication Ser. No. 62/277,343, filed Jan. 11, 2016.

BACKGROUND Field of the Invention

This invention relates to atomization of liquids and, more particularly,to novel systems and methods for separating larger droplets from smallerdroplets in cold air diffusers of essential oils and other aromaticmaterials.

Background Art

Mechanisms exist for altering a closed environment such as a room orhome with humidity. Likewise, mechanisms exist for removing humidity.Electronic and chemical mechanisms for destroying microbial sources ofundesirable scents exist. Meanwhile, sprays, evaporators, wicks,candles, and so forth also exist to distribute volatile scents,essential oils, liquids bearing scents, and so forth. These may beintroduced into breathing air, an atmosphere of a room, or any otherenclosed space.

Heating often destroys or at least changes the constitution of essentialoils. Thus, it has limitations. However, the evaporation rates oratomization rates of essential oils are often insufficient to provide acontrollable, sustainable, and sufficient amount of an essential oilinto the atmosphere. Thus, wicks having no air movement mechanism oftenprove inadequate.

Meanwhile, mechanisms that seek to copy vaporizers and moistureatomizers often damage surrounding equipment, furniture, and otherenvirons of a space being treated by essential oils. Moreover, thecontinuing “spitting” by atomizers of comparatively larger droplets notonly causes damage to finishes on surrounding surfaces, but wastes asubstantial fraction of the essential oil.

Essential oils are concentrated sources of aromas or scents. Theirextraction from source plants is sometimes complicated and comparativelyexpensive, based on the cost per unit volume of the essential oil.Therefore, colognes, other fragrance distribution systems, and the likeoften use high rates or fractions of diluents for essential oils. Theymay also use synthetic oils, water, and artificial scents that maydilute and not replicate the comforting, familiar, and natural essenceof pure, essential oils.

By whatever mode, systems to distribute essential oils often waste anexpensive commodity while damaging surroundings about their atomizers orother distribution systems. Thus, it would be an advance in the art toprovide an apparatus and method for distributing essential oils in assmall particles as possible, preferably vaporized, but having a sizesufficiently small that air drag forces sustain them by dominatinggravity forces tending to drift them out of the air. Thus diffusionefficiency needs to increase, while protecting surrounding areas. Itwould be an advance to do so while retrieving and recycling forre-atomization or diffusion droplets that are larger than those that maybe sustained by air motion to remain airborne once discharged intosurrounding air.

It would be a further advance in the art to quiet a diffuser. Thechatter of reciprocating pumps is annoying. The hiss of atomizersspraying air and entraining droplets therein often transmits into a roomat highly audible levels.

It would also be an advance in the art to improve separators andsilencers to make them smaller, more compact, and more mobile, so theymay be used with any source of air or atomizer. It would help to find asystem suitable for a room, or even carried in a vehicle. Adding aromasto vehicles has long been the purview of poorly constructed andshort-lived, absorbent materials filled with an oil and suspended by atether from a mount of a rear view mirror. Effective selection of scent,duration and intensity of scent, and other desirable controls have beeneffectively absent. Moreover, the complexities of atomizers, separators,and silencers sizes, ineffectiveness, and have likewise been a deterrentto rapid and simplified mechanisms for diffusing essential oils andother liquids.

It would be an advance in the art to provide an integrated, universalseparator and silencer. Simplifying and integrating are seriouschallenges. Controlling do not appear to be understood or applied. Itwould be a substantial benefit to a user to have a system tested andapplying operational characteristics effective to a separate and silencein a compact user.

BRIEF SUMMARY OF THE INVENTION

In view of the foregoing, in accordance with the invention as embodiedand broadly described herein, a method and apparatus are disclosed inone embodiment of the present invention as including a separator systemthat operates as a silencer and as a droplet separator for removingcomparatively larger droplets and leaving comparatively smaller dropletsentrained in a flow of air.

In certain embodiments, the overall system involves a reservoir operablyconnected by a line or tube drawing liquid from a reservoir into anatomizer. The atomizer may include a venturi as that word is understoodin engineering.

A venturi is a condition defining a throat with a decreasingcross-sectional area of flow moving toward a central or middle portionfollowed by an increasing cross sectional area in a subsequent trailingportion. At the narrowest part of the throat, a port or opening in thewall of the conduit permits a second material to enter into the flowthrough the venturi. The constant value of dynamic head constituted bypressure head and velocity head results in a reduced static pressurenear the midway point of the throat. This reduced static pressure drawsmaterial into the flow from the open port. A conventional carburetoroperates on this principle.

In other embodiments, the atomizer may rely on an eductor. An eductor isa different mechanism mechanically, aerodynamically, andhydrodynamically. For example, an eductor relies on direct momentumtransfer between an incoming jet and a surrounding fluid. By directcontact between the material in the jet with the surrounding material,the surrounding material receives momentum from the jet and therebyaccelerates, joining and broadening the jet, necessarily slowing it. Theacceleration of the surrounding material results in it being drawn awayfrom its original location, creating a draw bringing replacementmaterial in. Thus, an eductor operates as a pump in which acomparatively high speed jet induces the flow of a comparatively lowspeed or even stationary surrounding fluid. Thus the size of the jet andits total mass increase as its speed slows.

The eductor portion of the atomizer educts into a flow of air a liquiddrawn through the tube from the reservoir. The liquid is atomized by thevigorous flow of the air jet that causes the eduction, resulting in aGaussian distribution of liquid droplets.

The liquid droplets entrained in the airflow are cast into a firstseparation chamber or drift chamber in which they will eventually berequired to change direction. Typically, the educted flow will impact orstrike a wall opposite its nozzle that discharges the jets, resulting ina certain amount of adhesion and coalescence by comparatively largerdroplets, a change of direction of the airflow, with a consequent changeof direction of the comparatively smaller droplets remaining entrainedin the airflow.

Larger droplets that coalesce against a wall drip down out of theseparation chamber or drift chamber toward the reservoir. Dropletssufficiently small to remain entrained within the airflow changedirection, move away from the wall and eventually move toward an exit.

In certain embodiments, a silencer or air-blade silencer may be aportion of or may penetrate through a separator plate separating thefirst or initial drift chamber or separation chamber from a subsequentor second such chamber. In fact, the air blade itself may be acomparatively long, wide, and thin channel. By thin is meant that thecomparative thickness of the flow channel, compared to the widththereof, and compared to the longitudinal length measured along thedirection of flow through that channel is comparatively small. The widthand the length may have an aspect ratio (relationship, ratio) of aboutone. On the other hand, the aspect ratio of thickness to length orthickness to width, may be less than 0.5, and typically 0.2, 0.1, orless.

In operation, the air blade channel effectively sets up a boundary layerflow near the walls. As a result, the central core of flow through theair blade channel sets up a flow regime as known in fluid mechanics inwhich velocity of air along the central axis along the flow path in theair blade travels at maximum velocity and the velocity of air at thewalls is effectively zero.

Thus, a velocity profile is established as described in any text onfluid mechanics. Therefore, droplets are being shed as the flow slowstoward the outside walls, larger droplets being coalesced against thewalls upon contact. Comparatively smaller droplets capable of remainingin the airflow continue onward through the channel on a trajectoryvirtually identical to that of the air. Thus, one may see that the airblade operates as a separator channel.

The air blade feeds into a second drift chamber. The second driftchamber operates similarly to the first. Here, the flow through the airblade channel is directed vertically toward a fixed, horizontal wall inthe nature of a lid or cap over the second drift chamber. Thus, flowfrom the air blade is directed to strike the lid, and change direction.Again, impact against the lid or cap results in separation (byshattering, coalescing, or a combination) of comparatively largerdroplets. Likewise, comparatively smaller droplets capable of remainingentrained with the airflow stay with it, and are directed or shuntedaway from actual impact with the lid, remaining with the airflow. Forthe sake of completeness, it should be understood that entrainment is aterm of art, used in it engineering sense as defined in fluid mechanics.It is the mutual engagement of fluid particles, resulting from fluiddrag and momentum transfer therebetween. Ultimately, flows of air withtheir entrained, “comparatively smaller” droplets pass through thesecond drift chamber and eventually find their way to an exit port.

The exit port is intentionally offset so as not to align with the airblade. That is, for example, flow from the air blade (the think airflowfrom a separator tower) cannot pass directly toward and out of the port,without a change of direction. Typically, the port is set eccentrically,off center, with respect to the lid, and is registered 180 degrees outof phase with the air blade. Thus, the air blade discharges from itstower as a thin flow of air containing atomized droplets, to impingeagainst a solid portion of the lid, from whence the airflow must changedirection. It must flow through the second drift chamber, and ultimatelychange direction to again move vertically out through the exit port.

The offset of the exit port has been found to be extremely importantfrom both a separation view point (separating comparatively largerdroplets out from the flow) as well as a silencing perspective (reducingthe decibels of noise audible outside the system) during operation.Thus, the air blade silencer system includes and operates as a channelseparator or air blade separator and a drift chamber separator. Inaddition, the air blade silencer system operates as a noise reductionsystem removing significant noise, otherwise vert audible, originatingwith operation of the system in accordance with the invention.

A separator plate in certain embodiments of an apparatus in accordancewith the invention may operate similar to a separator plate in othersystems described in the references incorporated hereinabove byreference. For example, separator plates having a single aperture,multiple apertures, apertures near the center, apertures near the edges,and so forth have been disclosed in those documents. However, the smallaspect ratio of thickness to width and small aspect ratio of thicknessto length are new, unique to certain of the latest inventions ofApplicant.

Here, the separator plate is penetrated by a thin channel, through atower, that effectively travels vertically. In other embodiments, thechannel has traveled circumferentially in a spiral. In others, anannular channel carried the flow, and operated as a separator based onaerodynamic and hydrodynamic principles.

Here, the channel is not permitted to be fully annular, in order toprovide the offset of the air blade from the outlet port. This resultsin a reduction in sound of from about six to about 10 decibels.Typically, the hiss of the atomizer is silenced by about eight decibelsin sound amplitude.

Moreover, the offset results in two drift chambers and an air bladechannel (in the tower) all acting as separators. Thus, three separationprocesses occur resulting in virtually no “spitting” of comparativelylarger droplets. By comparatively larger droplets is meant those thatwill not sustain themselves indefinitely in a flow of air. That is, theyare sufficiently large in diameter and cross sectional area that theirmass becomes sufficiently large to overcome (e.g., dominate) theaerodynamic drag thereon in a flow of air.

Comparatively large droplets tend to drift out of an airstream landingon furniture, floors, counters, carpets, bedding, and the like in thevicinity of a diffuser. Thus, it has been found that offsetting the airblade from the outlet port by from about 90 to about 180 degreesprovides a reduction ad apparently entire elimination of substantiallyall comparatively larger liquid droplets.

Meanwhile, an optimum reduction in sound results with about a 180 degreerotation out of phase between the outlet port and the center of airblade (center line of flow).

In one embodiment, the air blade separator and silencer may have a neckfitted to an atomizer to receive flows therefrom. The neck may be fittedby a collar having a reduced or increased cross sectional area in orderto pilot radially and register in a circumferential direction with theatomizer.

In certain embodiments, the outer wall of the air blade channel (andtower) may actually be coincident with the wall of the neck. Meanwhile,an inner wall of the tower defining the air blade channel may be shapedto provide a drip edge for coalesced droplets that have returned to aconsolidated liquid and dripped down the inner wall of the towerdefining the air blade channel. Thus, a lower edge of the inner wall ofthe air blade channel may be angled to promote droplets collectingthereon to drift to a lowest point thereon. That angle toward the lowestpoint or drip point encourages collection along the drip edge withresulting coalescence and dropping from the drip point. Thus, if anindividual separates the silencer or separator from the atomizer, mostresidual oil does not remain.

Meanwhile, a drain or exit port for coalesced liquids within the bowl ofthe silencer or separator may be favored by a canting or tilting angleof the separation plate that operates as the bottom or floor of thebowl. In this way, any coalesced droplets within the bowl drip down tothe separator plate, which then passes them along its angled surfacetoward the exit or drain.

In certain embodiments, the neck of the silencer may register at aspecific point with the atomizer. For example, in one currentlycontemplated embodiment, the air blade is registered to be positionedopposite the inlet for the eductor.

Due to the vigor of the flow through the eductor, and the right-anglerelationship between the direction of the central axis of the flow (jet)out of the eductor compared to the flow direction of the air blade,there is virtually no probability that the largest of the comparativelylarger droplets will be passed through the air blade from the initialseparation chamber or directly from the educted flow. Thus, flow fromthe eductor progresses toward an opposite wall, where comparativelylarger droplets strike the wall of the first drift chamber. They may beshattered, coalesced, both, or otherwise altered.

Meanwhile, comparatively smaller droplets that remain with the airflowmay drift around the drift chamber, eventually finding their way withthe airflow into the air blade. Comparatively larger droplets initiallywith the airflow through this tortuous path are relegated to strike awall and coalesce, eventually to drip back into the reservoir. The capof the silencer is registered with the bowl in order to provide anoffset of 180 degrees between the center of the air blade and the outletport from the silencer or separator.

In order to minimize capillary action, a capillary break may be providedas a channel containing air and encircling substantially the entirecircumference of the cap. Thus, no capillary path exists from within thebowl to the outside edge between the bowl and cap.

Likewise, in the interest of maintaining a silencer or separator thatcan be handled, removed, cleaned, and the like, it is key to limit anyexcess amount of oil or other previously atomized liquid clinging tovarious surfaces. The drain may be provided with a surface tensionbreaker. Typically, the greatest surface tension is between the liquidand itself. However, surface tension also exists between the material ofthe silencer-separator and the oil. Accordingly, the drain hole or drainport in the separator plate may be provided with a surface tensionbreaker positioned therebelow. The surface tension breaker may simply bea sharp-cornered projection extending out from the wall or insidesurface of the neck to encourage any droplets forming in or around thedrain port to adhere thereto and drip away. By making comparativelysharp corners having a small or no chamfer for a corner break, surfacetension tends to draw liquids immediately toward the wall and away fromthe drain.

In one embodiment of a method of atomizing liquids in a flow of air, onemay provide a source of air and a source of liquid, thereafter atomizinga portion of the liquid into droplets by the flow of air. Providing afirst drift chamber requiring at least one change of direction prior toexiting the first drift chamber begins separation of droplets by size.

Then, providing a channel having a large aspect ratio of length oftravel compared to thickness of the flow, and a large aspect ratio ofwidth of the flow to the thickness of the flow provides centripetalseparation therein, another separation step. Providing a second driftchamber requiring at least one change of direction of the airflow priorto exit therefrom may include various mechanisms such as a change ofdirection, or several, as well as changes in cross sectional area forthe flow, thus speeding and slowing (or vice versa) the flow one or moretimes.

Each drift chamber may require one or more changes of direction, threechanges of direction of the flow being typical. An air blade wallenclosing the entire flow of air and droplets contained therewithin maypass between the first drift chamber and the second drift chamber. Anoutlet port from the second drift chamber is typically offset to causethe flow to change direction at least three times in order to pass fromthe air blade through the exit or outlet port.

An eductor may b provided to serve as an initial atomization deviceforming droplets of the liquid in the airflow. Integrating the seconddrift chamber with a suitable type of separator plate divides the firstdrift chamber from the second drift chamber. That separator plate mayinclude or have secured thereto a channel formed to extend between thechambers (separation chambers, drift chambers) on either extreme(typically top and bottom) of the separator plate. That channel may becharacterized by a length and minimum characteristic thickness. Thethickness serves best if substantially less than the length, andcalculated to establish a laminar flow profile (see any text on fluidmechanics, Reynolds number below 2100). Laminar or turbulent, it isstill effective to separate out comparatively larger droplets againstthe walls of the channel, while leaving entrained in the airflowcomparatively smaller droplets sufficiently small such that aerodynamicdrag of the air thereagainst is sufficient to overcome settling down bygravity or impingement against solid surfaces.

Certain methods of separating out comparatively larger liquid dropletsfrom comparatively smaller liquid droplets in a flow of air may includeproviding an atomizer atomizing a liquid in a flow of air, passing theflow of air into a first drift chamber requiring at least one change ofdirection between the atomization and exit therefrom, passing theairflow through a channel having an aspect ratio of a minimum width to alength of travel of from about one third to about one twentieth, andpassing the airflow through a second drift chamber requiring at leastone change of direction between introduction into the second driftchamber, and exit from the second drift chamber. The method or processmay continue by discharging the airflow containing only thenon-separated, comparatively smaller droplets of liquid entrainedtherein into the atmosphere surrounding the second drift chamber.

An apparatus may include a bowl, a neck connecting the bowl to a flow ofair an air blade constituting a channel having an aspect ratio ofminimum thickness to length of travel ranging from about 0.3 to about0.05 passing the airflow following atomization through the channel intoa drift chamber requiring at least one change of direction prior to exittherefrom. Then, an exit port offset away from the air blade dischargesthe flow, after requiring at least one change of direction therebetween.

A cap, separable from the bowl, such that the cap and bowl together formthe second drift chamber. The cap sits opposite (typically above) afloor operating as a separator plate. Together, the cap and separatorplate bound from above and below an interior volume of the second driftchamber conducting from its atomizer (source) the flow of air. The airblade channel may be constructed to be curvilinear. This provides moreavailable width (horizontally) perpendicular to the thickness (alsomeasured horizontally). Thus, when the channel is curved in acircumferential direction, the airflow is axial (vertical) through thechannel.

The second drift chamber is configured to have an exit port dischargingthe airflow in an axial direction substantially parallel to the flow inthe channel. The exit port is best offset from the channel to require atleast two changes (typically three or more) of direction of the airflowto pass from the channel of the exit port. Also, the flow mustaccelerate and decelerate, sometimes more than once each. One mayconsider the floor of the bowl, through which the air blade channelpasses to be a separator plate separating the atomizer from the seconddrift chamber. However, it is also proper to speak of everything betweenthe first and second drift chambers to be a “separator plate.” Aseparator plate is not simply a plate, or need not be. It may havevarious apertures, channels, and walls to effect a “separation” processin addition to the separation processes conducted in each drift chamber.It is simply more compact, and may rely on various processes ofacceleration, flow profiles, and the like to encourage separation oflarger droplets out of the flow. Larger droplets are those that tend todrift out of the air after discharge, and therefore need to be separatedout and returned to the reservoir of liquid to be atomized again.

A drift chamber formed in the atomizer will typically receive atomizedliquid in the airflow and collect a portion of the atomized liquid byimpact against a wall, from whence returning the collected atomizedliquid to a reservoir. Sufficiently small and dynamic atomized dropletsof liquids (still suspended in the airflow) pass through the separatorplate to the second drift chamber. Some pass all the way through to theexit, the objective being to pass only those that will remain suspendedin the room air, not allowing spitting or settling of the liquiddroplets on furniture and other surroundings.

Silencing and separation processes in a cold-air, essential-oil,diffuser apparatus and method pass flow through a channel havingcomparatively high aspect ratios of length to thickness and width tothickness. Curved, tapered, non-parallel, and quasi random surfacesreduce probability and power of resonant frequencies. Offsetting flowthrough a channel is followed by impingement against an obstructingsurface, redirection elsewhere within a drift (separation) chamber, andexiting through a smaller, and differently oriented exit port. Silencingis improved by changes of cross-sectional area creating high-pass andlow pass acoustic filters, changes of direction, and absorption ofacoustic energy in fluid-droplet-laden air.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of the present invention will become more fullyapparent from the following description and appended claims, taken inconjunction with the accompanying drawings. Understanding that thesedrawings depict only typical embodiments of the invention and are,therefore, not to be considered limiting of its scope, the inventionwill be described with additional specificity and detail through use ofthe accompanying drawings in which:

FIG. 1 is an upper perspective, exploded view of one embodiment of acomplete diffuser system fitted with a silencer-separator in accordancewith the instant invention;

FIG. 2 is an upper, perspective, assembled view thereof;

FIG. 3 is a lower, perspective, assembled view thereof;

FIG. 4 is an upper, perspective, exploded view of thesilencer-separator;

FIG. 5 is a lower, perspective, exploded view thereof;

FIG. 6 is an upper, more steeply angled, perspective view of the loweror bowl portion thereof;

FIG. 7 is a lower, perspective view of the bowl of FIG. 6;

FIG. 8 is a top plan view of the cap, and therefore thesilencer-separator in accordance with the invention;

FIG. 9 is a side, elevation, cross-sectional view of asilencer-separator in accordance with the invention;

FIG. 10A is a bottom plan view of a silencer-separator in accordancewith the invention;

FIG. 10B is a top plan view thereof;

FIG. 11 is a front elevation view thereof;

FIG. 12 is a rear elevation view thereof;

FIG. 13 is a right side elevation view thereof; and

FIG. 14 is a left side elevation view thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It will be readily understood that the components of the presentinvention, as generally described and illustrated in the drawingsherein, could be arranged and designed in a wide variety of differentconfigurations. Thus, the following more detailed description of theembodiments of the system and method of the present invention, asrepresented in the drawings, is not intended to limit the scope of theinvention, as claimed, but is merely representative of variousembodiments of the invention. The illustrated embodiments of theinvention will be best understood by reference to the drawings, whereinlike parts are designated by like numerals throughout.

Referring to FIG. 1, while continuing to refer to FIGS. 1 through 14generally, a silencer 10 or separator 10 may be configured as anair-blade, silencing, separator apparatus and method. Accordingly, itwill be appropriate to speak of the subsystem 10 as a silencer, aseparator, an air-blade, or the like. The subsystem 10 may also bereferred to as a silencer-separator, since it functions as both, and wasdesigned, experimented, evaluated, operated, redesigned, modified,dozens upon dozens of times in order to obtain its combination ofsilencing and separating effects.

By silencing is meant the reduction in sound propagated outside adiffuser 12 or system 12 in operation. By separating is meant theseparation from a flow of air, certain, entrained droplets in the flowof air. Typically, as used herein, the expression separator orseparating refers to removing “comparatively larger” droplets.Comparatively larger droplets refer to those droplets that aresufficiently large that their mass, and therefore their weight under theinfluence of gravity, are sufficiently large compared to theiraerodynamic drag in a flow of modest to velocity, typically thecirculation of room air, that such droplets will fall out of the flow ofair within the room, typically 15 to 20 feet.

However, comparatively smaller droplets remain in the airflow constitutethe objective. Thus, comparatively smaller droplets are those that aresufficiently small that they will drift in a flow of air at modestvelocities, typically associated with ventilation motion of the air in aventilated room, indefinitely. Indefinitely means at least an hour ormore, and will typically be several hours, or until the room air hasbeen effectively exchanged.

In a system 12 equipped with a silencer-separator 10, the system 12 iseffectively constituted as a cold-air, diffusion apparatus 12, alsoreferred to simply as a diffuser 12. A diffuser 12 may draw from areservoir 14 containing a suitable liquid. Liquids typically may includeessential oils, mixtures of solvents with the essential oils, emulsionsof water, other liquids, or the like. Typically, the content or liquidin a reservoir 14 is drawn through a tube 15 or line 15 penetrating to alocation near the bottom of the reservoir 14. An atomizer 16 drawsliquid content from the reservoir 14 through the line 15 to be atomized.By atomization is meant the breaking up of a liquid, flow of liquid, orthe like into a random distribution, which will typically be a Gaussiandistribution, also known as a normal distribution.

Atomization may be done by a venturi or an eductor. A venturi is aconduit narrowing to a throat through which a flow of fluid passes, theconduit progressing from a comparatively larger diameter to a smallerdiameter and ultimately to a narrowest diameter, followed by an increasein diameter. By the word diameter is meant hydraulic diameter. Ahydraulic diameter is four times the area divided by the wettedperimeter. In a circular cross-sectional area, hydraulic diameter equalscircular diameter. In a square cross section, hydraulic diameter equalsthe length of one side.

In any other shape of a cross section, the hydraulic diameter provides avalue that may be used for effective diameter in hydrodynamic oraerodynamic equations of flow. Hydraulic diameter relates thecross-sectional area to the shape of the perimeter or circumference ofor about a flow. Thus, in speaking of diameter, the expression meanseffective diameter or hydraulic diameter. That is, any time the worddiameter is used, what is meant is the effective diameter.

A venturi relies upon dynamic pressure head. Typically, in a flowthrough a venturi, dynamic pressure head is substantially constant.There is some amount of drag, but it is substantially negligible in manyinstances. Thus, assuming a constant, dynamic pressure head means thatthe static pressure contribution and the velocity contribution todynamic pressure head add to the same constant value throughout. Thus,whenever the cross-sectional area narrows, the velocity must increase.Thus, the velocity head component must increase, causing a reduction inthe static pressure head contribution.

The result of the reduction in static pressure head at the narrowestportion or the throat of a venturi results in a low pressure region thattends to draw against the walls. Thus, a penetration, tube, pipe, or aport in a wall, or the presence of a tube, inlet, or other access by asecond fluid at the exact throat (narrowest portion) of a venturi willresult in drawing that fluid into the flow.

An eductor is an entirely different mechanism. An eductor is a devicefound in virtually all gas stoves, gas furnaces (e.g., propane, naturalgas, butane, etc.) and has been for decades, in fact, over a century.Likewise, eductors are used in various pumping systems, particularly forpumping fluids that will damage pumps. Sewage is one example.

For example, pumping a flow of sewage sludge is not appropriate for amechanical pump. Damage by wear and corrosion would be swift andcertain. Instead, a cleaner fluid may be injected as a high speed jetrelative to a comparatively low speed flow of sludge. The high speed jetimparts momentum from itself (e.g., small mass, high velocity) to theflow of sludge (e.g., large mass, comparatively low velocity).

An eductor thus relies on direct momentum transfer between a first flowat a comparatively higher velocity into a second flow at a comparativelylower velocity. Momentum transferred from the higher speed jet into thelower speed surrounding fluid results in motion of the comparativelyslower mass of fluid, resulting in drawing in more of that surroundingfluid into the jet as it progresses forward.

Eductors 18 have been described in considerable detail, along with theiroperation, in the references incorporated hereinabove by reference.Typically, an eductor 18 may be made up of a variety of components,resulting in a flow of air therethrough shattering or comminutingliquid, received through the tube 15, in an eductor jet 28, not shown inentire detail here, but included in great detail in the referencesincorporated herein by reference.

The atomizer 16 may include a housing 17, as a part of which the eductor18 may fit its own seals 22 air jet nozzles 24 including a jet aperture25 all fitted into a housing 26 for containment. The eductor nozzle 28receives air from the jet opening 25 through the eductor nozzle 28, thusdrawing with it liquid captured therebetween, that is, between the airnozzle 24 and the eductor nozzle 28. Thus, out of an opening in theeductor nozzle 28 sprays an airflow containing a distribution ofdroplets of the liquid content drawn from the reservoir 14.

The droplets from the eductor 18 enter a separation chamber 20 a ordrift chamber 20 a. The drift chamber 20 a may also be referred to as aseparator 20 a. A separator 20, generally, operates by severalmechanisms. First of all, the specific separation chamber 20 a asconstituted by the housing 17, presents a wall against which the flowwill impinge. Comparatively larger droplets will tend to strike thewall. Comparatively smaller droplets will tend to remain in the flow ofair.

That is, comparatively larger droplets having more mass, and thereforemore weight, associated with greater momentum within themselves, aresufficiently heavy that they cannot change direction due to theinsufficient aerodynamic drag of air flowing thereby. Accordingly,comparatively larger droplets strike a wall, coalesce there or shatter.To the extent that the droplets coalesce, they will drift downwardtoward the reservoir 14. To the extent that the droplets shatter,comparatively larger portions may again be subjected to coalescingagainst the wall. Sufficiently small droplets will be entrained (carriedby aerodynamic drag) within the airflow, eventually finding their wayout of an exit from the drift chamber 20 a. A separator plate 30 maydivide the separator chamber 20 a of the atomizer 16 from a secondseparation chamber 20 b or drift chamber 20 b of the silencer-separator10. Trailing letters or reference numerals indicate a specific instanceof the item type identified by the numeral.

The silencer-separator 10 may begin at its lower extremity with a neck32. The neck 32 may include a collar portion 34 or collar 34 that has asmaller or larger diameter than does the neck 32. In the illustratedembodiment, the collar 34 has a smaller diameter, in order to fit intothe housing 17 of the atomizer 16. In other embodiments, the collar 34may have a larger diameter than the neck 32, thus forming a detent 34 toconstrain the neck 32 within the housing 17 of the atomizer 16. In otherembodiments, threads may substitute for any other retainers.

However, in the illustrated embodiment, one purpose for the collar 34 isto provide a close fit against the surface 36 in the housing 17.Likewise, a registration 38 or notch 38 in the neck 32 fits against amatching or mating protrusion on the surface 36. Thus, by not beingthreaded, the neck 32 may slide into the housing 17, with the collar 34snuggly fitting against the surface 36, and being rotatable forregistering the registration 38 or notch 38 therein.

Registration 38 assures that the channel 40 or air blade 40 itself isopposite the eductor nozzle 28 of the atomizer 16. This, as it turnsout, is important for reducing sound. Sound waves propagate up throughthe channel 40 or air blade 40. The channel (cavity) 40 may be called anair blade 40 and creates a blade of air or an air blade, because it hasa comparatively narrow thickness relative to both its overall width, andits overall length in the direction of flow (e.g., vertically).

The air blade 40 or channel 40, by being positioned obliquely, in fact aright angle, in the illustrated embodiment, with respect to the flow ofthe eduction spray, provides much damping, and uncoupling of thesoundwaves by virtue of the difference in characteristic lengths betweenit and the surrounding drift chamber 20 b. Various characteristiclengths (e.g., diameter, varied diameter along its height, depth, varieddepth in view of the capered bottom surface, and so forth) existthroughout.

Referring to FIG. 1, while continuing to refer generally to FIGS. 1through 14, a silencer-separator 10 may include a channel 40 or airblade 40 defined by a wall 42 around a tower 43. The wall 42 may includean inner portion 42 a and an outer portion 42 b. Typically, the outerportion 42 b will extend down and through the separator plate 30.Accordingly, the actual outer wall 42 b may eventually be coincident orshare an inner surface with the neck 32 at the bottom of thesilencer-separator 10.

Referring to FIGS. 2 and 3, and FIGS. 1 through 14 generally, one willsee that assembled, the system 12 may include a reservoir 14, threadedonto an atomizer 16, with a silencer-separator 10 fitted into the upperopening of the atomizer 16. Effectively, the bowl 44 or bowl portion 44of the silencer-separator 10 defines the wall surrounding the seconddrift chamber 20 b. By drift chamber 20 is meant that an airflowcontaining droplets flows through the drift chamber 20, permittingcomparatively larger (higher momentum, lower drag) droplets to drift outof the flow of air to impinge against solid surfaces, there coalescingto become a film, rivulets, and drops that eventually drip downward toreturn to the reservoir 14. The bowl 44 is closed on top by a cap 46.The cap 46 is comparatively snuggly fitted in order to not pass anysignificant amount of fluids through the seal or fit therebetween.

Referring to FIGS. 4 through 10, while continuing to refer generally toFIGS. 1 through 14, the bowl 44 and cap 46 may be provided with aregistration 48 or notch 48 adapted to receive a protrusion in the cap46, fitted thereto. One will note that the registration 48 isillustrated as a notch, but could be a protrusion, a spline, a key, orthe like. Typically, a collar on the cap 46 may slide with a frictionfit into the bowl 44.

One benefit of a sliding fit, snap fit, or the like is that theregistration 48 may be matched with a corresponding registration 49 onthe cap 46. Thus, the bowl 44 and cap 46 may be visibly rotated withrespect with one another in order to match up the registration 48 at theappropriate location. The effect of the registration 48 is to establishthe position of the air blade 40 with respect to the outlet 50.Typically, the registration 48 and its matching pin 49 may be reversedor may be changed in any suitable manner, so long as registrationtherebetween is promoted.

Effectively, the outlet 50 serves best if offset by at least 90 degreesfrom the plane or center plane that would effectively form areflectively symmetric surface passing vertically through the tower 43,air blade 40, and its walls 42. As a practical matter, it is proper tospeak of the air blade 40 as the channel 40, or as the flow of air 51therethrough. Thus, the flow 51 through the channel 40 represents an airblade 40, 51. Similarly, one may speak of the air blade as the structure42 or walls 42 that form the channel 40 that passes the flow 51. Thus,herein, the term air blade 10, 40, 43, 51 should be clear from itscontext.

It has been found that the outlet 50 serves best if offset by 180degrees from the channel 40, or the center line or center plane throughthe channel 40. One may think of a center plane through the channel 40as a vertical plane extending upward and horizontally bisecting both theinner wall 42 a and outer wall 42 b around the channel 40. The separatorplane or dividing plane would thus form a vertical plane of symmetry forthe air blade 40, the flow 51, the walls 42, the bowl 44, the cap 46,and so forth.

Referring to FIGS. 5 through 10, while continuing to refer generally toFIGS. 1 through 14, the silencer-separator 10 is not entirelysymmetrical or axially symmetrical. For example, the cap 46 and bowl 44are largely point symmetrical or axially symmetrical. Nevertheless, thewalls 42 are clearly not line or point symmetrical, being offset fromthe center, and curved along a circumferential direction to be uniformlyspaced away from the bowl 44 itself.

The bowl 44 and cap 46 may be fitted together with a notch registration38 and a corresponding pin 49 or peg 49. Meanwhile, proceedingcircumferentially around virtually the entire circumference of the cap46 may be a capillary break 52. A capillary break 52 constitutes a gap52 sufficiently large that capillary action of the contained fluiddroplets coming from the eductor and coalescing in the bowl 44 will notcross. Accordingly, oil will not collect or seep out of the gap or thesealing surfaces between the bowl 44 and the cap 46.

For example, the vertical surface 53 may be comparatively tight, andtherefore may attract, due to surface tension, collection of a certainquantity of oil or other contents being coalesced from droplets.However, the capillary break 52 interferes with transport to anywhereoutside the bowl 44.

Regarding asymmetric features of the silencer-separator 10, one willimmediately note that in FIG. 9 the inner wall 42 a angles downward. Thelower edge 54 acts as a drip edge 54. For example, the channel 40between the inner wall 42 a and outer wall 42 b constituting the walls42 or wall region 42 develops a slot flow profile as well understood inengineering.

Any basic, engineering, fluid-mechanics book will describe conditionsand show the flow profile for a laminar flow and for a turbulent flow ina narrow passage. In either event, a boundary layer near the surfaces ofthe walls 42 a, 42 b will form, moving very slowly and collecting liquiddroplets that touch the walls 42 a, 42 b.

Droplets thereby adhere to the walls 42 and other liquids coalescethereagainst. A direct result is a flow down the inside surfaces of thechannel 40. That flow along the outer wall 42 b will eventually find itsway down into the housing 17 and neck 32 of the atomizer 16, and therebyto the reservoir 14. Meanwhile, any coalesced droplets that impingeagainst the inner surface of the bowl 44 will drain downward toward thedrain 58.

One will note that the drip edge 44, by being angled downward from oneextreme to the other, creates a drip point 56 at the lowest location 56of the drip edge 54. Droplets coalescing against the inner wall 42 a,within the channel 40 will flow down to the drip edge 54, and thence tothe drip point 56, where they will form droplets that will readily dropback into the housing 17 from the neck 32. Droplets tend not to stopalong the drip edge 54, but collect and move downward toward the drippoint 56. Thus, droplets collected from the channel 40 will typicallyadhere to the wall 42, move toward the outer wall 42 b, and thereby dripback through the neck 32 and into the housing 17 and reservoir 14.

The drain 58 may be provided with a breaker 60 or surface tensionbreaker 60 constituted by a sharp edge or multiple sharp edges on aprotrusion 60 away from the neck 32. This protrusion 60 may have sharpedges in order to promote the formation of droplets therearound,stripping them from the drain 58, so they do not collect, becomeblocked, or otherwise form larger droplets suspending from the drain 58.The breaker 60 operates as a surface tension breaker 60 providing asolid surface promoting flow away from the drain 58.

In general, the capillary break 52, the surface tension breaker 60, thedrip edge 54 and drip point 56, and so forth are innovations deemedappropriate in order to encourage complete draining of liquids from thesilencer-separator 10. Typically, the system 12 may be taken apart, thereservoirs 14 may be changed out with different contents, and so forth.By encouraging prompt and complete draining of all liquids back to thereservoir 14, the silencer-separator 10 is maintained cleaner, will beless likely to drip or otherwise transfer oily contents to the hands orclothing of a user, or to a surface on which any component may betemporarily set when dismantled.

Referring to FIG. 9, while continuing to refer generally to FIGS. 1through 14, one will note that the port 50 or outlet 50 also includes awall 62 protruding into the drift chamber 20 b formed by the bowl 44 andcap 46. This provides several benefits. First, the wall 62 provides arequirement for a change of direction, and multiple changes of directionof airflows. For example, an airflow 51 exits substantially vertically.Thence, the flow 51 will impinge against the cap 46, particularly, aninner, horizontal surface 64 thereof.

Thereafter, the flow 51 will be diverted to flow in other directionsthroughout the drift chamber 20 b. To the extent that airflow progressesradially, it may impinge against the inner surface 66 of the bowl 44.Ultimately, a flow 70 may exit the outlet 50. However, at least threechanges of direction must occur in most of the flow 51 in order for theflow 51 or droplets and air within the flow 51 to exit the channel 50,since the air blade 51 comes to a halt due to striking the insidesurface 64 of the cap 46, progress horizontally, radially, and the likein order to reach the outlet 50. The flow must then turn to progressvertically out through the port 50.

Moreover, the change of shape between the comparatively thin but wideair blade 51 from the channel 40 and the comparatively narrow, typicallycircular or otherwise cylindrical shape of the outlet 50, requiresexpansion of the flow into a larger area, out of a comparatively smallercross-sectional area. It then reduces from that comparatively largercross-sectional area back into an even smaller cross-sectional area ofthe exit 50.

This repeated change of cross-sectional area available to accommodatethe flow also results in drifting, slowing, and jinking (zig-zagging,sharp turns back and forth, darting), which action therefore providemore dwell time, repeated acceleration and deceleration of flow, and soforth to promote more drifting and smashing by comparatively largerdroplets against solid surfaces.

Only droplets small enough that their mass, momentum, and fluid dynamicdrag permit them to remain with the air flow through all its twists,turns, stops, starts, accelerations, and decelerations will remain inthat flow when it exits the systems 10, 12.

This is the ultimate definition of “small” droplets, those that exit theseparator 12 with the air flow. At any space, conduit, path, location,or the like, the “comparatively larger droplets” are those that strike asolid surface and coalesce. “Comparatively smaller droplets” remainentrained in, and exit that space with, the flow of air therethrough.

The silencer-separator 10 illustrated has proven highly effective ineliminating the sound of hissing generated by an atomizer 16, andparticularly the eductor 18. It is also very effective at eliminatingcomparatively larger droplets in the airflow 70 proceeding from theoutlet 50. Those comparatively larger droplets are those that wouldotherwise drift downward at an unacceptable rate to land on furniture,counters, and flooring. The objective is for all droplets released toevaporate or drift with room air indefinitely or sweep out withventilation air exiting the treated space.

The sound is minimized, typically reduced by from about six to about tendecibels in volume (intensity, amplitude), and typically provides on theorder of about eight decibels of reduction of sound when the outlet 50is 180 degrees out of phase with respect to the tower 43 of the airblade 51. Meanwhile, the elimination of comparatively larger droplets or“spitting” droplets that are sufficiently large to settle out onfurniture or other surfaces nearby is eliminated so long as the cap 46has been rotated to place the outlet 50 at about 90 degrees or greaterout of phase with the center plane of the air blade 40.

Other features of a silencer-separator 10 in accordance with theinvention are the various changes in cross-sectional area, shape, and soforth. By providing suitable taper to the shape of the bowl 44, thevariation in diameter tends to avoid establishing a single resonantlength that may promote resonant frequencies of audible sound wavesduring operation of the system 12. Likewise, by canting or tilting theseparator plate 30 that operates as a floor 30 of the bowl 44, a singleresonant length or height is less likely. Similarly, below the floor 30(i.e., separator plate 30), vertical height is affected by the angledseparator plate 30.

The shape of the tower 43 and air blade 51 is capable of accomplishingseveral functions. First, maintaining a distance from the exit 50 oroutlet port 50 is accommodated by wrapping the walls 42 along the pathsubstantially parallel to the surface 66 inside the bowl 44. Also, thisprovides for maintaining distance away from the outlet 50. Although astraight (non curved) channel 40 may operate to provide the separationfunction of the channel 40, coalescing droplets along the walls 42 a, 42b, the sound is prevented from obtaining consistent characteristiclengths by the curvature, and its resulting distribution of the flow 51throughout the drift chamber 20 b. In other words, care has been takento reduce the incidence of single, characteristic lengths that mightpromote or support resonant frequencies that may increase propagation ofsounds.

Referring to FIGS. 8 through 14, the various views of thesilencer-separator 10 illustrate the relative dimensions and shapesinvolved. For example, the neck 32 is comparatively smaller, and capableof fitting within a housing 17 of an atomizer 16 available. Meanwhile,the comparatively larger diameter of the bowl 44 provides substantialdrift space, substantial increase in cross-sectional area of the flow,multidirectional dispersion of the flow 51, and so forth. Meanwhile, therear elevation, front elevation, right side elevation, and left sideelevation views show substantial symmetry, with only small variations.Nevertheless, internally, the pleasing symmetry of the exterior isabsent and does not limit the ability to form non-symmetric shapes, flowareas, transitions, changes of direction, and the like therewithin.

One will also note the manufacturing elegance of the outer wall 42 bbeing essentially coincident with the neck 32 generally. Meanwhile, theformation of the channel 40 by the inner wall 42 a, may be molded fromthe two sides or surfaces of the separator plate 30 that forms the floor30 of the bowl 44, and the sealing of the first drift chamber 28 in thehousing 17. An additional separator plate, or even a micro-cyclone maystill be placed below the system 12.

The present invention may be embodied in other specific forms withoutdeparting from its purposes, functions, structures, or operationalcharacteristics. The described embodiments are to be considered in allrespects only as illustrative, and not restrictive. The scope of theinvention is, therefore, indicated by the appended claims, rather thanby the foregoing description. All changes which come within the meaningand range of equivalency of the claims are to be embraced within theirscope.

What is claimed and desired to be secured by United States LettersPatent is:
 1. A method of atomizing liquid in a flow of air, the methodcomprising: providing a source of the liquid and a source of the air,the air pressurized to urge a flow characterized by thickness, width,and length; providing an atomizer dispersing into the flow a portion ofthe liquid as droplets entrained therein; providing a first driftchamber receiving the flow and changing a direction thereof prior toexiting therefrom; providing a channel conducting the flow, having firstand second ends, and defining an aspect ratio of length to thicknessthereof greater than one, and an aspect ratio of length to width thereofgreater than one; and providing a second drift chamber connected to thesecond end, opposite the first drift chamber at the first end, imposingat least one change of direction of the flow prior to exit therefrom. 2.The method of claim 1, wherein the first drift chamber is shaped toimpose more than one change of direction of the flow.
 3. The method ofclaim 2, wherein the second drift chamber imposees more than one changeof direction of the flow.
 4. The method of claim 3, wherein each of thefirst drift chamber and the second drift chamber impose upon the flow atleast three changes of direction, an acceleration, and a deceleration.5. The method of claim 1, further comprising providing a channelcomprising an air blade wall enclosing the entire flow of air, anddroplets contained therewithin, passing as a blade of air, having athickness is less than a width thereof and less than a length of theflow therethrough, between the first drift chamber and the second driftchamber.
 6. The method of claim 5, further comprising providing anoutlet configured as an exit port from the second drift chamber, theoutlet offset from the air blade to cause the flow to change directionat least three times in order to pass from the air blade through theexit port.
 7. The method of claim 6, further comprising providing aneductor as the atomizer.
 8. The method of claim 4, further comprisingintegrating the second drift chamber with a separator plate dividing thefirst drift chamber from the second drift chamber, the channel passingthrough the separator plate.
 9. The method of claim 1, wherein the firstdrift chamber is separated from the second drift chamber by a channelextending therebetween and characterized by walls defining a channellength and channel thickness, substantially less than said channellength and calculated to establish a laminar flow profile effective toseparate out comparatively larger droplets against the walls, whileleaving entrained in the flow comparatively smaller dropletssufficiently small that aerodynamic drag of air thereagainst issufficient to overcome settling by gravity or impingement of thecomparatively smaller droplets against solid surfaces.
 10. A method ofseparating out comparatively larger liquid droplets from comparativelysmaller liquid droplets in a flow of air, the method comprising:providing an atomizer atomizing a liquid in a flow of air; passing theflow of air into a first drift chamber requiring at least one change ofdirection between the atomizing and an exit therefrom; passing theairflow through a channel having an aspect ratio of a minimum width to alength of travel of from about one third to about one twentieth; passingthe airflow through a second drift chamber requiring at least one changeof direction between introduction of the flow into the second driftchamber, and exit thereof from the second drift chamber; and dischargingthe flow containing only the comparatively smaller droplets of liquidentrained therein into an atmosphere surrounding the second driftchamber.
 11. An apparatus comprising: a bowl; a neck connecting the bowlto a flow of air containing droplets of a liquid, comprisingcomparatively larger droplets and comparatively smaller droplets; an airblade constituting a channel having an aspect ratio of minimum thicknessto length of travel ranging from about 0.3 to about 0.05 protruding intothe bowl; a first drift chamber passing the flow through at least onechange of direction prior to exiting therefrom into the channel; and anexit port discharging the flow from the bowl at a location offset awayfrom the air blade radially to impose two changes of direction in theflow between the channel and the exit port.
 12. The apparatus of claim11, further comprising a cap separable from the bowl, the cap and bowltogether forming a second drift chamber: a separator plate separating aninterior volume of the second drift chamber from a source of the flow ofair to allow substantial flow therebetween only through the channel. 13.The apparatus of claim 11, wherein the channel terminates at a lower endwith a drip edge urging a portion of the liquid coalesced from thecomparatively larger droplets to move to a lowest point on the dripedge.
 14. The apparatus of claim 13, wherein the channel is curved in acircumferential direction with respect to a vertical axis through thebowl.
 15. The apparatus of claim 14, wherein the bowl has a plate at anaxially lower end, perforated to pass the portion of the liquidcoalesced to exit to a reservoir therebelow.
 16. The apparatus of claim15, wherein the cap includes an exit port discharging the flow in anaxial direction substantially parallel to the flow through the channel.17. The apparatus of claim 11, wherein the flow coalesces a portion ofthe comparatively larger droplets by subjecting them to lateral drifttoward a wall of the channel due to laminar flow in the channel.
 18. Theapparatus of claim 11, further comprising an atomizer providing theflow.
 19. The apparatus of claim 18, further comprising a separatorplate separating the atomizer from an interior volume of the bowl exceptthrough the channel.
 20. The apparatus of claim 18, wherein the atomizercomprises a drift region collecting a portion of the comparativelylarger droplets and returning them to a reservoir therebelow.